Molecular dynamics simulations of nanopolycrystals

Abstract

Nanopolycrystals are polycrystalline metals with an average grain size below 100 nm and exhibit extraordinary strength values. In contrast to the coarsegrained polycrystals, the confinement by grain boundaries of the plastic deformation in the grains approaches limits, where the conventional theories break down. In the grain size regime 10-20 nm, molecular dynamics simulations play a crucial role to elucidate the possible and surprising deformation mechanisms in nanocrystalline metals although the MD method uses assumptions, which ad hoc do not allow for a straightforward extrapolation to experimental conditions. This chapter presents the nanocrystalline-specific methods for MD simulations with their subtleties and summarizes the deformation mechanisms in nanopolycrystals with their signatures on the (experimental) deformation behavior. A comprehensive understanding on the interplay of the deformation mechanisms is suggested in this chapter, which is closed with a list of still-open issues in the field.